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Magnetoresistive element including two ferromagnetic layers

a magnetoresistive element and ferromagnetic layer technology, applied in the field of magnetoresistive elements, can solve the problems of insufficient bias magnetic field, large variation in output of the read head, and low yield of the read head

Active Publication Date: 2010-11-30
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This configuration reduces variations in output asymmetry and enhances the reliability of magnetic disk drives by stabilizing the bias magnetic field application and preventing degradation of the hard magnetic layer's crystallinity and orientability.

Problems solved by technology

Meanwhile, read heads incorporating conventional MR elements of three-layer structure have a disadvantage that, when a large number of read heads are manufactured to the same specifications, asymmetry of output of the read heads greatly varies and consequently the yield of the read heads is low.
A first factor is that a sufficient bias magnetic field is not obtainable because of a low saturation magnetization of the bias magnetic field applying layer.
A second factor is that a reduction in read gap length causes a reduction in distance between the bias magnetic field applying layer and each shield, and consequently the occurrence of leakage of a magnetic field from the bias magnetic field applying layer to the shields becomes noticeable.
The technique disclosed in JP 10-312512A, when applied to a read head incorporating an MR element of three-layer structure, cannot sufficiently reduce variations in asymmetry of output of the read head, however.
It is therefore difficult with the above technique to eliminate the second factor described above.
As a result, the reliability of a magnetic disk drive including the magnetic head decreases.

Method used

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  • Magnetoresistive element including two ferromagnetic layers
  • Magnetoresistive element including two ferromagnetic layers
  • Magnetoresistive element including two ferromagnetic layers

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0058]Embodiments of the present invention will now be described in detail with reference to the drawings. Reference is first made to FIG. 4 and FIG. 5 to outline the configuration and manufacturing method of a thin-film magnetic head of a first embodiment of the invention. FIG. 4 is a cross-sectional view illustrating a cross section of the thin-film magnetic head perpendicular to the medium facing surface and the top surface of the substrate. FIG. 5 is a cross-sectional view illustrating a cross section of a pole portion of the thin-film magnetic head parallel to the medium facing surface.

[0059]The thin-film magnetic head of the embodiment has a medium facing surface 20 that faces toward a recording medium. The thin-film magnetic head includes: a substrate 1 made of a ceramic material such as aluminum oxide and titanium carbide (Al2O3—TiC); an insulating layer 2 made of an insulating material such as alumina (Al2O3) and disposed on the substrate 1; a first shield 3 made of a magne...

second embodiment

[0140]A second embodiment of the invention will now be described. FIG. 20 is a cross-sectional view illustrating a cross section of an MR element of the second embodiment perpendicular to the medium facing surface 20 and the top surface of the substrate 1. In the MR element of the second embodiment, out of the high saturation magnetization layer 43A and the hard magnetic layer 43B of the bias magnetic field applying layer 43, at least the high saturation magnetization layer 43A is formed by lift-off.

[0141]Reference is now made to FIG. 21 to FIG. 25 to describe a method of manufacturing the MR element of the second embodiment. The steps of the method of manufacturing the MR element of the second embodiment are the same as those of the first embodiment up to the step of forming the MR stack 30 by patterning the multilayer film for the MR stack 30 using the mask 53 (see FIG. 12).

[0142]FIG. 21 illustrates the next step. In this step, first, with the mask 53 of FIG. 12 left unremoved, th...

third embodiment

[0158]A third embodiment of the invention will now be described. FIG. 26 is a top view of the MR stack 30 and the bias magnetic field applying layer 43 of the MR element of the third embodiment. As shown in FIG. 26, the plane geometry of the bias magnetic field applying layer 43 of the third embodiment includes a first portion 431, and a second portion 432 located between the first portion 431 and the rear end face 30b of the MR stack 30. The first portion 431 and the second portion 432 are each rectangular in shape. The dimension W2 of the second portion 432 taken in the direction parallel to the front end face 30a of the MR stack 30 is smaller than the dimension W1 of the first portion 431 taken in the direction parallel to the front end face 30a.

[0159]The bias magnetic field applying layer 43 of the third embodiment includes the high saturation magnetization layer 43A and the hard magnetic layer 43B, like the first and second embodiments. The position of the boundary between the...

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Abstract

A magnetoresistive element includes a first and a second shield, and an MR stack disposed between the shields. The MR stack includes a first and a second ferromagnetic layer, and a nonmagnetic spacer layer disposed between the ferromagnetic layers. The first and second ferromagnetic layers have magnetizations that are in directions antiparallel to each other when no external magnetic field is applied to the layers, and that change directions in response to an external magnetic field. An insulating layer is formed to touch a rear end face of the MR stack and the first shield, and a bias magnetic field applying layer is formed above the insulating layer with a buffer layer disposed in between. The bias magnetic field applying layer includes a hard magnetic layer and a high saturation magnetization layer. The high saturation magnetization layer is located between the rear end face and the hard magnetic layer, but not located between the first shield and the hard magnetic layer.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a magnetoresistive element and a method of manufacturing the same, and to a thin-film magnetic head, a head assembly and a magnetic disk drive each including the magnetoresistive element.[0003]2. Description of the Related Art[0004]Performance improvements in thin-film magnetic heads have been sought as areal recording density of magnetic disk drives has increased. A widely used type of thin-film magnetic head is a composite thin-film magnetic head that has a structure in which a write head having an induction-type electromagnetic transducer for writing and a read head having a magnetoresistive element (that may be hereinafter referred to as MR element) for reading are stacked on a substrate.[0005]MR elements include GMR (giant magnetoresistive) elements utilizing a giant magnetoresistive effect, and TMR (tunneling magnetoresistive) elements utilizing a tunneling magnetoresistive effect....

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): G11B5/33
CPCB82Y25/00G01R33/093G01R33/098G11B5/3932H01L43/12G11B5/3912H10N50/01
Inventor MACHITA, TAKAHIKOHIRATA, KEISHIMAZAWA, KOJIMIYAUCHI, DAISUKE
Owner TDK CORPARATION